I've changed a few things: one cutoff pot instead of two (a mod of the WSG filter circuit), played with different capacitor values for the oscillators, and also experimented with a different way of soldering in which I stuck the diodes and resistors straight to the pots, but differently than I had before (it worked and is cleaner).

Looking at the schematic you posted i wonder about the osc 6 (lfo), it seems to be "grounded at both ends" what does it do ? What is ic connected to ?_________________Stay Cool
Mikael
http://www.mikmo.dk

It is indeed grounded at both ends. I don't know where I read it (possibly somewhere on this thread even) but this kind of 'LFO' works not by directly modifying the output of the oscillators, but by interfering with the way the other oscillators get power, since all of the oscillators are part of the same IC. If you watch the video I linked to, you can see and hear how the LFO wreaks havoc on the other oscillators, especially when the voltage is sagged. Actually, depending on the settings of the voltage sag knob and the LFO, something very unusual happens. When the sag is dropped to half or lower, and the LFO is set fully clockwise, the unit(s) produce almost white noise, which the red unit is doing at the very beginning of the video (sag=1/2, LFO=max). Later on, the LFO is dropped to about 1/2 (at around 1:45 in the video) which makes the oscillators cycle on and off. This cycling only happens when BOTH the voltage sag AND the LFO are dropped to about 1/2: if the sag is set fully clockwise, changing the LFO speed doesn't produce cycling, but works almost like a conventional LFO (although it is kind of subtle).

Sorry I can't offer a technical explanation... I'm not an expert on circuits by any means. All I can tell you is I like what it does. Hehehe..

It is indeed grounded at both ends. I don't know where I read it (possibly somewhere on this thread even) but this kind of 'LFO' works not by directly modifying the output of the oscillators, but by interfering with the way the other oscillators get power, since all of the oscillators are part of the same IC. If you watch the video I linked to, you can see and hear how the LFO wreaks havoc on the other oscillators, especially when the voltage is sagged.

Sounds kinda like the Cacophonator. Extra oscillators mess with the current draw, but don't get hooked up as sound sources. Cool idea.

Yes indeed I think it may have been the Cacophonator that I 'borrowed' the LFO idea from. I must've looked at about 100 different pages on the Internet and the same amount of schematics before I mashed together my mixed up mess of a circuit. Love these things though! 2 more in the works right now.

I have been experimenting with adding momentary buttons to the Hetrodyne Space Explorer so it can be played "percussively" instead of "droning". However, depending on where in the circuit I add the momentary buttons, some strange problems have occurred. Perhaps someone can shed some light on what is happening and where/how to add momentary switches.

Location 1-
I inserted momentary normally open SPST push button switchs into the oscillator outputs (from pins 2,4,6, and 8 ) just before the "S2, S3, S4 and S5" toggle switch locations as the schematic shows. When the newly added momentary buttons are pressed, the oscillator signal is heard loud and clear but when the button is released it is not completely silenced. You can still hear the oscillators humming away, although faintly. I would assume that the oscillators would be completely silent if the output signal path is disconnected, but this is not the case. I thought it was just a breadboard bleed through problem but I have soldered the circuit onto a pcb with components and put it all in an enclosure and can still hear the oscillators faintly.

Location 2-
I have found that when inserting a momentary normally open SPST push button switch in the feedback loop between, say pins 1 and 2, that it stops the oscillator completely, which stops the faint bleed through problem. But this set-up causes a new problem, which is: When the oscillators are being mixed through the diodes rather than the resistors, and the new momentary buttons are pressed, random volume drops and signal cancellations happen between the different oscillators (not the clipping/gating effect that the diodes normally produce). However, when the oscillators are mixed through the resistors this phenomenon does not happen.

Just to restate my question:

When I add momentary buttons to the oscillator outputs, the oscillators can still be faintly heard when the buttons are in the "off/open" position. When I put the momentary button between pins 1 and 2, random volume drops and signal cancellations happen between the separate oscillators when mixing through the diodes. Where/how do I add momentary switches to the circuit?

On The outsider schematic, we can see that the pwm oscillation is built around a 4148 diode. Could someone explain me why we need this diode ? in an electronically way ? It's a bit of theory that i don't get yet.

the feedback resistor determines how fast the capacitor charges,
a diode+resistor in parallel (pointing towards the capacitor) makes it charge faster in the on state,
but when it's in the off state, it will discharge at normal speed, as if the resistor+diode are not there.
The opposite will happen when it points towards the output.
This change in speed in either the off or on state will make that state shorter = pulse width

Maybe you can put a large resistor (100k or more) to ground after the switch, to make that it remains at ground, I did not test this but i think it should work...

Thanks for the reply Kabzoer. I've tried the resistor to ground with several different values but the oscillator can still be heard, although it is a little quieter. I decided to try putting the momentary button in the feedback loop of the oscillator instead of on the output. I've attached a schematic of the circuit. With this setup, when the momentary buttons are pressed simultaneously, the oscillators drop randomly in volume or cut out completely. Any ideas why its doing this? I think a "transistor buffer" may be needed at the outputs, but I'm not sure how to go about it. Thanks for any help!

I know this is almost a year old, but...
When I put N.O. momentary switches in circuits like these, it's between the input pins' caps and ground (for instance, pin 1 on a 40106 going through switch, into cap). Voltage regulators (78L05, for example) seem to help iron out a few glitches, but I've just started experimenting using those with the CMOS chips._________________"The life of a repo man is always intense."

ebay is a pretty good place for knobs for cheap (from china)...though it may take 2-3 weeks to arrive depending on the shipping used, etc..

also the cheap banana jacks on ebay from china are great for circuit bending due to the fact that they have the metal socket expose which is great for using as contact points using your fingers, i recently stumbled upon. but use super glue or lock-tite to ensure you don't one day pull out the entire socket with banana plug as the nuts and threads are pretty bad...

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